For easy carrying by users, common carry-on package bags, such as paper bags that are often considered more environmentally friendly, are often manufactured so as to provide carrying handles mounted on a bag body, or form an opening, through cutting the bag at a location close to an opening of the bag, to receive fingers to extend therethrough. However, adding carrying handles to the bag requires handling with a large amount of human labor and is not suitable for automatized manufacturing, so that the amount of human labor and time cost consumed are great. Cutting the bag to form a through opening, although being a process that can be carried out by machines, often causes stress concentration in the bag at a location close to the through opening so that the bag is susceptible to deformation and breaking when loaded with heavy articles, thus making the bag not durable. Thus, these two ways of manufacturing both need further improvement concerning cost, durability, and convenience of use.